|Gilmer D. Gaston, P.E., PTOE||August 14, 2002|
As a traffic engineering professional, I feel compelled to comment on the Access Board's proposed Draft Guidelines for Accessible Public Rights-of-Way. I formerly managed the traffic signals section for the City of Houston, so I have a feel for how severe these requirements will impact the agencies.
While the guidelines were undoubtedly prepared by a group of well meaning individuals. They contain several items that could have severe and unintended consequences. I have provided a few comments on some of what I feel are the more onerous sections of the document.
1105.3 Pedestrian Signal Phase Timing. All pedestrian signal phase timing shall be calculated using a pedestrian walk speed of 3.0 feet per second (0.91 m/s) maximum. The total crosswalk distance used in calculating pedestrian signal phase timing shall include the entire length of the crosswalk plus the length of the curb ramp. If applied uniformly, this could have severe consequences on overall traffic signal system operations and vehicle delay. Traffic Engineers already have the ability to use a 3.0 fps or 3.5 fps walking speed at locations frequented by children, the elderly, or otherwise mobility impaired. These lower walking speeds should be applied only on a case by case basis. Alternatively, with the ATC controller, it will likely be possible to provide a second walk and pedestrian clearance time that could be activated by receiving an extended "call" from the pedestrian pushbutton, i.e., maybe the pedestrian holds in the button for 3 seconds to bring up the longer pedestrian timings.
1105.7 Turn Lanes at Intersections. Where pedestrian crosswalks are provided at right or left turn slip lanes, a pedestrian activated traffic signal complying with 1106 shall be provided for each segment of the pedestrian crosswalk, including at the channelizing island.
Is there actual crash data that supports the need for this measure? We know that there are a lot of pedestrian accidents at intersections; however, it is my understanding that in most of those instances the pedestrian is not using or following the guidance of the existing pedestrian signals. This item would probably put an unnecessary burden on agencies to retrofit existing intersections for little, if any, safety benefits, and a likely decrease in the operational benefits of right-turn lanes.
Something that I didn't see, that I believe could be useful is a recommended maximum distance from the crosswalk for the placement of pedestrian pushbuttons.
The US Congress is known for passing good intended legislation that often results in unintended actions by the public. This leads to more legislation and more requirements as it can produce unintended results. A possible,
unintended consequence of unnecessarily stringent requirements could be a reduction in the number of crosswalks. Some intersection crossings may be signed for no pedestrians because the disbenefits to intersection operations could outweigh providing a crossing that complies with these guidelines.
If you have any questions, or comments, let me know. I may provide additional comments later, as I have a chance to further review these materials.
Gilmer D. Gaston, P.E., PTOE
Sr. Transportation Manager
Pape-Dawson Engineers, Inc.
San Antonio, Texas
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